KR19990037191A - Iron oxide yellow pigment, method for producing iron oxide yellow pigment and uses thereof - Google Patents

Abstract

FIELD OF THE INVENTION The present invention relates to a process for the production of iron oxide yellow pigments by precipitation from ferrous chloride yellow pigments, ferrous chloride and alkaline components, and the use thereof.

Description

Iron oxide yellow pigment, method for producing iron oxide yellow pigment and uses thereof

FIELD OF THE INVENTION The present invention relates to a process for the production of iron oxide yellow pigments by precipitation from ferrous chloride yellow pigments, ferrous chloride and alkaline components, and the use thereof.

Precipitation methods for preparing iron oxide yellow pigments have been known for a long time. Conventional procedures of this method are described, for example, in Ullmanns Enzyklopaedie der technischen Chemie, 5th edition, volume A 20, p. 297 and below. Ferrous sulfate (II) sulfate formed during pickling of the steel sheet or ferrous sulfate (II) sulfate formed during the production of titanium dioxide by the sulfate process is usually used as a raw material.

A large amount of FeCl ₂ is formed during the production of synthetic rutile for the production of TiO ₂ . In the pickling industry, the tendency to use hydrochloric acid for pickling has increased over the years, resulting in the formation of large amounts of FeCl ₂ during pickling. In addition, the chloride process is increasingly used worldwide to produce titanium dioxide. Therefore, more and more ferrous chloride-containing solutions are being formed from these methods and must be converted as much as possible into useful materials.

One common method of utilizing FeCl ₂ waste is a spray roasting process that oxidatively hydrolyzes ferrous (II) chloride or ferric chloride (III) chloride at high temperatures (typically above 1000 ° C.). . Hydrochloric acid, which may be recycled as a useful material, such as iron oxide, typically hematite, and to the pickling process, is the final product in this process.

In general, iron oxide suitable for the production of light ferrite is obtained from this process without any specific purification step. If a soft ferrite is to be prepared from iron oxide obtained in this way, the iron chloride solution used has to undergo further purification in advance, and this method is quite expensive. As more and more iron chlorides are produced, mainly of lower quality, and the capacity of the ferrite market is limited, there is a search for alternative ways to produce useful materials from iron chlorides obtained in this way. Landfilling or dumping the iron oxide solution directly to the sea is impossible for ecological reasons.

It was therefore an object of the present invention to provide a method for converting an iron oxide solution into a high quality useful material in a simple, low cost way.

The iron oxide yellow pigment according to the invention and the process according to the invention have proved possible to achieve this object.

Accordingly, the invention is of 62.0 to 64.0 CIELAB lightness L ^* of the unit, 8.5 to 10.5 CIELAB units for a pure color a ^* value, and 48.5 to 50.5 b ^* value of the CIELAB units, and the bleaching (whitening) upon is 81.6 to 82.5 CIELAB units Brightness L ^* , a ^* value in CIELAB units of 3.8 to 4.8 and b ^* value in 37.5 to 39.5 CIELAB units, and a chromium content of less than 40 mg per kg iron oxide yellow pigment, 0.05 to 0.3 wt% chloride for iron oxide yellow pigment Content, iron oxide yellow pigment having a manganese content of 0.007 to 0.055% by weight relative to the iron oxide yellow pigment.

In addition, the present invention

a) To an acidic ferric chloride (II) chloride solution having a FeCl ₂ content of 50 to 450 g / l, an amount of alkaline component sufficient to adjust the pH of the solution to 3-5 is added with vigorous stirring,

b) optionally, flocculant is added to this solution before or after addition of the alkaline component,

c) optionally, oxidation is carried out after addition of the alkaline component and optional flocculant,

d) the solid formed after the treatment in a) to c) is separated from this solution,

e) 4 to a molar amount of iron (ie, iron from iron hydroxide and iron from unreacted iron compound) in the total nucleus suspension in the α-FeOOH nuclei suspension prepared by precipitation; Add in an amount corresponding to 8 times,

f) heating the mixture obtained in e) to a temperature of 30 to 95 ° C., preferably 30 to 85 ° C., particularly preferably 55 to 75 ° C., with thorough mixing,

g) oxidation is then effected with an oxidizing agent added such that 0.5 to 10 mol% of iron per hour, preferably 0.5 to 2.0 mol% of iron per hour, is oxidized and at the same time using an alkaline component to 0.01 to 0.4 pH units. Increase the final pH from 3.0 to 5.0 at a rate per hour,

h) optionally, oxidation continues at a constant pH of 3.0 to 5.0,

i) oxidation is stopped as soon as the ferrous (II) content in the suspension is less than 1 mol%,

j) and finally a process for producing the iron oxide yellow pigment by precipitation, characterized in that the solid of i) is separated, washed, dried and polished.

It is preferable to use sodium hydroxide solution, sodium carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide or ammonia as the alkaline component.

Ferrous chloride (II) chloride solution from steel pickling or ferrous chloride (II) chloride solution from TiO ₂ production by the chloride method can be used.

The method according to the invention can be advantageously carried out as follows.

To a ferrous chloride (II) chloride solution having a FeCl ₂ content of 50 to 450 g / l, a sodium hydroxide solution is added with vigorous stirring in an amount of pH adjusted to 3-5. Another alkaline component such as Ca (OH) ₂ , Na ₂ CO ₃ or ammonia or the like may be used in place of sodium hydroxide solution. In addition, the sedimentation behavior of the hydroxide or carbonate sludge obtained can be improved by the addition of flocculent aids. Known flocculating aids such as polyacrylates or other materials with similar action can be used. It may also optionally be followed by oxidation to improve the precipitation properties. Oxidation also results in the conversion of several metal cations to higher valence oxides or hydroxides that are easier to separate.

The hydroxide or carbonate sludge formed can be separated by sedimentation, filtration or using a separator. The optimal choice of suitable equipment or suitable method depends on the exact test conditions, mass flow and raw materials used.

The amount of iron in the total nuclear material was transferred to the α-FeOOH nuclear suspension prepared by the precipitation method, where the nucleus has a BET surface area of, for example, 65 m ² / g. (Ie iron from iron hydroxide and iron from unreacted FeCl ₂ ) is added in an amount corresponding to 4 to 30 times. Preferably, the suspension obtained is heated to a temperature of from 30 to 95 ° C, preferably from 30 to 85 ° C, particularly preferably from 55 to 75 ° C. When this temperature is reached, the oxidation is carried out using an oxidant and at the same time the final pH is increased to 3.0 to 5.0 at a rate of 0.01 to 0.4 pH units / hour. The rate of oxidation depending on the rate of addition of the oxidant, temperature, mixing in the vessel and pH should preferably be 0.5 to 10 mol% iron per hour, particularly preferably 0.5 to 2.0 mol% iron per hour. If the rate of oxidation is significantly slower than the lower limit, this method becomes uneconomical, and if the rate of oxidation is certainly faster than the upper limit, an iron oxide yellow pigment is obtained with an unwanted red tint.

This pigment suspension is worked up by known filtration, drying and polishing steps.

The following are examples of oxidants that can be used.

-Oxygen in the atmosphere

Pure oxygen

Ozone

-H ₂ O ₂

-Sodium hypochlorite or bleach or calcium hypochlorite

-Chlorite or chlorate

Perchlorate

Nitrate

- Goat

It is preferable to stop the oxidation as soon as the Fe (II) content in the suspension is less than 1 mol%. The oxidation may be further advanced until the reaction is complete.

Apart from the use of ferrous chloride (II) chloride solutions, mixtures of ferrous chloride (II) chloride and ferrous sulfate (II) sulfate solutions can also be used for both nucleation and pigment production. It is a preferred embodiment to use only ferrous chloride (II) chloride solutions. For example, if ferric chloride (III) is previously reduced to ferrous chloride (II) chloride using metal iron, ferric chloride (III) formed during the production of TiO ₂ by the chloride method may also be used. .

The obtained iron oxide yellow pigment is particularly suitable for coloring plastic materials and paper, and for preparing colored preparations such as latex paints, lacquers and dyes. Iron oxide yellow pigments can be used for coloring structural materials. It is also suitable for the production of colorants in the food industry.

Unless stated otherwise, parts and percentages of the following examples are given in parts by weight and percentage by weight.

The color tone was determined by the method described below.

1. Preparation of Alkyd Resin Lacquer for Pure Color Measurement

Weighing Of Pigment:

Fe-Red (Hematite) 1.00 g

Fe-Sulfur (Guyrite) 0.80 g

Fe-black (magnetite) 1.00 g

Pigments were prepared as non-drying test binder excipients using a disc pigment grinder (grinding machine). Test binder excipients (pastes) consist of two components.

Component 1:

Component 1 was an alkyd resin binder excipient based on linseed oil and phthalic anhydride. This is a prerequisite for test binder excipients for color pigments, similar to the specifications given in the standards DIN EN ISO 787-24 (October 1995), ISO 787-25: 1993 and DIN 55983 (December 1983). Previously, SACOLYD L 640 (registered trademark) (Krems Chemie Co., Ltd.), which was previously ALKYDAL L 64 (registered trademark) (manufactured by Bayer AG), was used. .

Component 2:

Component 2 is a flowable additive that is added to ensure the thixotropic behavior of the paste. The additive used here is used at a concentration of 5.0% of LuvoTHIX HT (registered trademark of Lehmann & Voss & Co.), a hydrogenated castor oil in powder form.

Rubotics HT was dissolved in Zacollide L 640 at 75-95 ° C. The cooled, compressed mass was passed through a triaxial roll mill once. This step completed the paste.

Disc pigment grinders (mills) were used as described in DIN EN ISO 8780-5 (April 1995). An Engelsmann JEL 25/53 mill with a disk effective diameter of 24 cm was used. The rotational speed of the lower disk was 75 min ⁻¹ . A load weight of 2.5 kg was applied to the load sirup to set the force between the disks to about 0.5 kN. The above mentioned amounts of pigment and 5.00 g of paste were dispersed in three stages of 25 revolutions each according to the method described in section 8.1 of DIN EN ISO 8780-5 (April 1995).

The pigment-paste mixture was then applied to a paste tray having a function similar to that of the paste tray of DIN 55983 (December 1983). The doctor blade attached to the paste tray was pulled to create a smooth surface across the recess of the tray filled with the pigment-paste mixture. In this process, the doctor blade was moved in one direction at a speed of about 3-7 cm / s. This smooth surface was measured in minutes.

2. Whitening (color intensity)

Pigments were prepared using a disc pigment grinder (grinding machine) as a non-drying test binder excipient. Test binder excipients (pastes) consist of two components.

Component 1:

Component 1 was an alkyd resin binder based on linseed oil and phthalic anhydride. This binder is similar to that given in the standard DIN EN ISO 787-24 (October 1995), ISO 787-25: 1993 and DIN 55983 (December 1983) as a prerequisite for test binder excipients for pigment coloring. Zacolide L 640 was used.

Component 2:

Component 2 is a flowable additive added to ensure the thixotropic behavior of the paste. The additive used herein is used in a powder, modified hydrogenated castor oil, at a concentration of 5.0% of Rubotics HT.

Rubotics HT was dissolved in Zacollide L 640 at 75-95 ° C. The cooled compacted mass was passed through a triaxial roll mill once. This step completed the paste.

Disc pigment grinders (mills) were used as described in DIN EN ISO 8780-5 (April 1995). Engelsmann JEL 25/53 mill with a disk effective diameter of 24 cm was used. The rotational speed of the lower disc is about 75 min ⁻¹ . A 2.5 kg load weight was applied to the load stud to set the force between the disks to about 0.5 kN.

Commercially available titanium dioxide pigment BAYERTITAN R-KB-2 (registered trademark) (manufactured by Bayer Agesa) was used as the whitening agent. The composition of R-KB-2 corresponds to the composition of Form R 2 in ISO 591-1977. If another R 2 pigment is used instead of R-KB-2, different CIELAB coordinates can be obtained from the colorimetric measurements.

0.400 g of pigment, 2.000 g of Bayertitanium R-KB-2 and 3.00 g of paste were dispersed in five stages at 25 revolutions in accordance with the method described in DIN 8.1 of DIN EN ISO 8780-5 (April 1995).

The pigment-paste mixture was then applied to a paste tray having a function similar to that of the paste tray of DIN 55983 (December 1983). The doctor blade on the paste tray was pulled over a recessed portion of the tray filled with the pigment-paste mixture to create a smooth surface. During this process, the doctor blade was moved in one direction at a speed of about 3-7 cm / s. This smooth surface was measured in minutes.

3. Colorimeter

A spectrophotometer (“colorimeter”) of measuring geometry in d / 8 was used without a gloss trap. These measurement geometries are described in ISO 7724 / 2-1984 (E) Section 4.1.1, DIN 5033 Part 7 (July 1983) Section 3.2.4 and DIN 53236 (January 1983) Section 7.1.1 .

A DataFLASH 200 measuring instrument supplied by Datacolor International was used.

The colorimeter was calibrated against white, ceramic working standards as described in ISO 7724 / 2-1984 (E) 8.3. The reflection data of the working standard for the ideal matte white body is stored in the measuring instrument so that all color measurements are obtained for the ideal matte white body after calibration using the white working standard. Black spot correction was performed using a black hollow body supplied by a colorimetric manufacturer.

4. Color Measurement

Any glossy traps present were cut off. The temperature of the colorimeter and test specimen was about 25 ° C ± 5 ° C.

4.1 Measurement of Lacquer Coating Film

The coating was placed on the colorimeter such that the measuring hole covered the center point of the lacquer coating. Wherever the coating is to be in full contact. The measuring hole shall be completely covered with a lacquer coating. Then measurements were taken.

4.2 Measurement of Paste Tray

After coating on the paste tray, color measurement was performed immediately. The filled paste trays were placed in the colorimeter in such a way that the measuring holes completely covered the recesses of the trays coated with the paste. Wherever the coat is to be tight. Then measurements were taken.

5. Calculation of CIE Coordinates

The CIE 1976 (L ^* , a ^* , b ^* ) coordinates (abbreviated as CIELAB) of the reflection spectrum depend on the constraints during measurement and evaluation. Data corresponding to a wavelength range of 400 nm to 700 nm and an interval of 20 nm can be applied to the DataPlace 2000 colorimeter in use (state of 7/97).

Only L ^* , a ^* and b ^* coordinates are given. All other variables are unnecessary.

The CIE coordinates L ^* , a ^* and b ^* of 1976 were measured from the reflection spectra measured according to the calculation given in ASTM E 308-1985, paragraph 7. The luminescence function of the standard emission C type and the 2 ° standard observer of ASTM E 308-1985, Table 5.6 was used. The wavelength range was 400 nm to 700 nm. The wavelength spacing was 20 nm. No gloss was taken out of the calculation. L ^* , a ^*, and b ^* were the approximations of all numbers.

L ^* a ^* b ^* color coordinates, referred to as CIE coordinates in DIN 5033 part 3 (July 1992). In ISO 7724 / 3-1984, the abbreviation CIELAB color stereogram is introduced. Coordinates have no units.

6. Determination of chromium and manganese content

Chromium and manganese contents were measured by ICP-MS. The detection limit of this method is 10 μg / kg.

7. Determination of Chloride Content

Chloride content was determined by chromatography.

The invention is illustrated by the following examples, which do not limit the scope of the invention.

<Example>

108.6 L yellow nucleus composition (BET specific surface area 61 m ² / g, 72.7 g / L FeSO ₄ , 36.0 g / L α-FeOOH) was placed in a stirrer equipped with a pH regulator and an air sparge. 169 L of a pretreated ferrous chloride (II) chloride solution containing 228.6 g / L FeCl ₂ were fed to this nuclear suspension. Then sodium hydroxide solution [300 g / l] was added at a rate such that the pH of the suspension increased by 0.2 units per hour. At the same time, the batch was oxidized with 80 liters of air per hour. When the pH reached 3.85, the pH no longer increased. This pH was kept constant with sodium hydroxide solution. The spreading system was left running. The reaction was terminated as soon as the Fe (II) content was less than 1 mol%.

The obtained iron oxide yellow pigment was filtered, washed with water, spray dried and ground on a steam jet mill.

This product showed the following pure color and color properties, respectively, compared to Bayferrox 3905 (by Bayer Agesa):

Measurement of color intensity (when whitening with Bayer titanium R-KB2):

Color Intensity: 100% (by: Viperox 3905 Standard 87)

Delta a ^* : 0.1 CIELAB unit

Delta b ^* : -0.6 CIELAB units

Absolute value:

L ^* : 82.1 CIELAB units

a ^* : 4.2 CIELAB units

b ^* : 38.0 units of CIELAB

Measurement of color intensity (in pure color; by Viperox 3905 Standard 87)

Delta L ^* : -0.1 CIELAB units

Delta a ^* : -0.1 CIELAB units

Delta b ^* : -0.7 CIELAB units

Absolute value:

L ^* : 63.4 CIELAB units

a ^* : 9.0 CIELAB units

b ^* : 48.9 CIELAB units

Cr content: 10 mg / kg pigment

Mn content: 0.013% based on pigment

Cl content: 0.12% based on pigment

Comparative Example

108.6 L yellow nucleus composition (BET specific surface area 61 m ² / g, 72.7 g / L FeSO ₄ , 36.0 g / L α-FeOOH) was charged to a stirrer equipped with a pH regulator and an air sparge. 169 L of an untreated ferrous chloride (II) chloride solution containing 228.6 g / L FeCl ₂ was fed to this nuclear suspension.

Then sodium hydroxide solution [300 g / l] was added at a rate such that the pH of the suspension increased by 0.2 units per hour. At the same time, the batch was oxidized with 80 liters of air per hour. When the pH reached 3.85, the pH no longer increased. This pH was kept constant with sodium hydroxide solution. The spreading system was left running. The reaction was terminated as soon as the Fe (II) content was less than 1 mol%.

The obtained iron oxide yellow pigment was filtered, washed with water, spray dried and ground in a steam jet mill.

This product showed the following pure color and color properties, respectively, as compared to Viperox 3905 (by Bayer Agesa):

Measurement of color intensity (when whitening with Bayer titanium R-KB2):

Color intensity: 100% (by: Viperox 3905 Standard 87)

Delta a ^* : 0.1 CIELAB unit

Delta b ^* : -0.4 CIELAB units

Absolute value:

L ^* : 82.1 CIELAB units

a ^* : 4.3 CIELAB units

b ^* : 38.2 CIELAB units

Measurement of color intensity (in pure color; by Viperox 3905 Standard 87)

Delta L ^* : -0.7 CIELAB units

Delta a ^* : -0.1 CIELAB units

Delta b ^* : -1.9 CIELAB units

Absolute value:

L ^* : 62.7 CIELAB units

a ^* : 9.1 CIELAB units

b ^* : 47.7 CIELAB units

Cr content: 180 mg / kg pigment

Mn content: 0.017% based on pigment

Cl content: 0.12% based on pigment

The present invention provides a method of using FeCl ₂ waste solution to convert the iron oxide solution into a high quality useful material at the lowest cost and as simple as possible.

Claims (15)

a) for pure color, lightness L ^* 62.0 to 64.0 CIELAB units, a ^* value 8.5 to 10.5 CIELAB units, and b ^* value 48.5 to 50.5 CIELAB units; b) at whitening, brightness L ^* 81.6 to 82.5 CIELAB units, a ^* value 3.8 to 4.8 CIELAB units, and b ^* value 37.5 to 39.5 CIELAB units; And c) 0.007 to 0.55 weight percent Mn, 0.05 to 0.3 weight percent Cl and less than 40 mg / kg Cr based on the pigment Iron oxide yellow pigment. a) adjusting the pH of the solution to 3-5 by vigorously mixing a sufficient amount of alkaline components in 50-450 g / l acidic FeCl ₂ solution, b) optionally, adding the flocculent aid to the FeCl ₂ solution of step a) before or after the addition of the alkaline component or concurrently with the addition of the alkaline component, c) optionally oxidizing the solution of step a) or b), d) separating this solution from the solid produced in steps a), b) or c), e) the solution formed in step d) into the α-FeOOH nuclear suspension prepared by the precipitation method in an amount corresponding to 4 to 8 times the total iron molar amount based on the iron hydroxide and the unreacted iron compound in the nuclear suspension. Adding step, f) heating to 30-95 ° C. with thorough mixing of the suspension formed in e), g) adding enough oxidizing agent to oxidize 0.5-10 mole% of iron per hour to oxidize the product of step f) while simultaneously providing sufficient alkaline components to raise the pH at a rate of 0.01 to 0.4 pH units / hour. Adding to increase the final pH to 3.0 to 5.0, h) after step g), optionally continuing the oxidation while maintaining a constant pH between 3.0 and 5.0, i) stopping oxidation when the Fe (II) content in the suspension of step g) or h) is less than 1 mol%, j) separating, washing, drying and polishing the iron oxide yellow pigment from step i) Iron oxide yellow pigment production method by precipitation comprising a. The method of claim 2, wherein the temperature in step f) is 30 to 85 ° C. 4. The method of claim 2, wherein the temperature in step f) is 55 to 75 ° C. 4. The process of claim 2 wherein the rate of oxidation in step g) is from 0.5 to 2.0 mole percent per hour. The method of claim 2 wherein the alkaline component is selected from the group consisting of sodium hydroxide, sodium carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, calcium oxide, calcium hydroxide and ammonia. a) adjusting the pH of the solution to 3-5 by vigorously mixing a sufficient amount of alkaline components in 50-450 g / l acidic FeCl ₂ solution, b) optionally, adding the flocculent aid to the FeCl ₂ solution of step a) before or after the addition of the alkaline component or concurrently with the addition of the alkaline component, c) optionally oxidizing the solution of step a) or b), d) separating this solution from the solid produced in steps a), b) or c), e) the solution formed in step d) into the α-FeOOH nuclear suspension prepared by the precipitation method in an amount corresponding to 4 to 8 times the total iron molar amount based on the iron hydroxide and the unreacted iron compound in the nuclear suspension. Adding step, f) heating to 30-95 ° C. with thorough mixing of the suspension formed in e), g) adding enough oxidizing agent to oxidize 0.5-10 mole% of iron per hour to oxidize the product of step f) while simultaneously providing sufficient alkaline components to raise the pH at a rate of 0.01 to 0.4 pH units / hour. Adding to increase the final pH to 3.0 to 5.0, h) after step g), optionally continuing the oxidation while maintaining a constant pH between 3.0 and 5.0, i) stopping oxidation when the Fe (II) content in the suspension of step g) or h) is less than 1 mol%, j) separating, washing, drying and polishing the iron oxide yellow pigment from step i) Iron oxide yellow pigment prepared by the precipitation method comprising a. A structural material comprising the iron oxide yellow pigment of claim 1. A method of coloring a structural material comprising adding the iron oxide yellow pigment of claim 1 to the structural material. Paper or plastic material comprising the iron oxide yellow pigment of claim 1. A method of coloring a paper or plastic material, comprising adding the iron oxide yellow pigment of claim 1 to the paper or plastic material. A paint or lacquer comprising the iron oxide yellow pigment of claim 1. A method of coloring a paint or lacquer comprising adding the iron oxide yellow pigment of claim 1 to the paint or lacquer. A colorant comprising the iron oxide yellow pigment of claim 1. A method for producing a colorant, comprising adding the iron oxide yellow pigment of claim 1 to the colorant.